Hello, I have a 400w HPS thats rated for 24,000 hours life, Ive only used it for about 9 months, 12hrs a day. Not that its getting bad or anything its still bright but when should I think about replacing it? I know Im no where near the 24,000 hrs but I also know that every day I lose a bit of light strength vs a new bulb, so when does it get to the point that I just need a new bulb? Any ideas? Thanks guys, its been a great first year indoor growing, I have all you to thank for my success, some failures too but thats my fault but over all I have supported my medical needs pretty well, only having to seek out supply this last month due to bad timing, its still a victory to me. Thank you all here at GC!